3 Answers
3

Technically "pale" refers to the saturation of the color, and "light/dark" refers to luminance, or the perceived brightness.

In AmE usage however, light can also mean a color that is not intense. I can't think of an instance where pale could be used for a color that is intense but light (or bright).

As I mentioned in my comment, in general conversation, you can use pale or light interchangeably when referring to a color and be understood. If the register is more formal and you're writing for a UK English audience, you should follow the advice in your book just to be certain your phrasing won't seem odd.

For each of the examples below, I went to DuckDuckGo.com and searched for images that matched the term. I had success with each color except for pale dark green - I ended up searching for "pale dark green" fabric to find an image where the color filled the frame. I picked from the first few results the ones I felt were distinct enough to show the difference. There is not a definite line where we can say "this green is pale to everyone who looks at it". Click on the image to see the original sized image.

This is both a light green and a pale green:

This is a light green but not a pale green:

This is bright green (both light in luminance and intense in color):

This is a pale dark green (might also be called gray-green):

This is a dark green (not pale This color is often called emerald or emerald green):

@Colleen V: So we can use light with yellow or pink. Should I ignore the note in the book? You disagree with the notion it has put, right?
– YuriMar 24 '16 at 14:36

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@Azad I think like everything in English, it depends on the context. If you're speaking informally, I think you would be understood if you said "pale yellow" or "light yellow" and you wouldn't sound odd (at least in the US). If you are writing formally for a British audience, I would follow the book's advice.
– ColleenV♦Mar 24 '16 at 15:04

I see, so it's mainly the matter of register and locality. Thanks 😊
– YuriMar 24 '16 at 15:12

I emphatically agree that "pale" is a term of saturation and "light" is a term of luminance. As demonstrated in this brilliant answer, a color can be light and pale or light and not pale. I would argue further a color can be dark, yet pale, such as a desaturated brown.
– bubblekingMar 24 '16 at 15:28

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I agree with all of these except "pale dark," which sounds weird to me.
– sumelicMar 24 '16 at 19:15

According to Google NGram, pale rather than light is the preferred term for most of the colours that I tried. The difference is much greater for yellow than other colours, and for BrE than AmE. Cream and pink are very much more common than pale yellow and pale red, though cream may include the dairy product as well.

The only colours I have found where light was the preferred term were brown (AmE and BrE) and grey/gray (AmE only).

For yellow, which is perceived as a bright colour, pale is the preferred term, and for brown, which is perceived as a dark colour, light is the preferred term.

Pale in AmE is more "literary" and light is more colloquial (unless you're speaking with a designer). Did you limit the search to the British corpra?
– ColleenV♦Mar 24 '16 at 14:35

An NGram comparing pale/light yellow as a noun in the US and GB corpora between 1900 and 2000 shows that pale occurs more often in both, but a much more often in GB than US (determined by a quick and dirty subtraction) pale yellow_NOUN:eng_us_2012,pale yellow_NOUN:eng_gb_2012,light yellow_NOUN:eng_us_2012,light yellow_NOUN:eng_gb_2012 Substituting other colors for yellow is interesting. Try pale blue versus light blue blue_NOUN:eng_us_2012,pale blue_NOUN:eng_gb_2012,light blue_NOUN:eng_us_2012,light blue_NOUN:eng_gb_2012
– ColleenV♦Mar 24 '16 at 14:59

@colleenV: interesting. Do Americans spell yellow differently, or something? I didn't know that you could specify parts of speech and corpora in a search: thanks for that!
– JavaLatteMar 24 '16 at 15:48

I'm a little on the fence about specify the color as a noun though. I think you can do pale yellow _NOUN_ as well. That might tell us if there is an adjective/noun difference.
– ColleenV♦Mar 24 '16 at 16:03

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I agree - technical usage isn't "more correct". It's more important to be precise in some situations than in others. 'I saw a rider on a pale horse' potentially conveys so much more meaning than saying 'I saw man riding a white horse.', but the more precise version would be better if you were explaining what happened to the police.
– ColleenV♦Mar 24 '16 at 17:13

Yes, Varun KN thanks for your comment. Though I just don't understand why 'pale' can be used with some colors instead of 'light'. It seems it has something to do with collocation that I can't find a list for.
– YuriMar 24 '16 at 9:57

Actually let me edit the title to make my point clearer. Sorry for being ambiguous in first place.
– YuriMar 24 '16 at 9:57

but 'light skin' is kind of permanent feature, while 'you look pale' is more like temporary effect of you being exhausted or sth.
– YabkoMar 24 '16 at 19:39

@Yabko I'm not sure about BrE, but in AmE "pale skin" can be a permanent feature, but it describes almost white/colorless skin, or skin that lacks melanin. Light skin seems to be relative to dark skin and could refer to skin that has some color, so it would depend on the context how close to pale skin it is.
– ColleenV♦Mar 28 '16 at 21:03